Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 25 August 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 237 Issued at 2200Z on 25 Aug 2021

IA. Analysis of Solar Active Regions and Activity from 24/2100Z to 25/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C1 event observed at 25/0124Z from Region 2860 (S27E28). There are currently 2 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be very low with a chance for a C-class flares on days one, two, and three (26 Aug, 27 Aug, 28 Aug).

IIA. Geophysical Activity Summary 24/2100Z to 25/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 406 km/s at 25/0050Z. Total IMF reached 11 nT at 25/0402Z. The maximum southward component of Bz reached -8 nT at 25/0402Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 125 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on days one, two, and three (26 Aug, 27 Aug, 28 Aug).

III. Event probabilities 26 Aug-28 Aug
Class M 05/05/05
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 25 Aug 084
Predicted 26 Aug-28 Aug 084/084/085
90 Day Mean 25 Aug 079

V. Geomagnetic A Indices
Observed Afr/Ap 24 Aug 005/004
Estimated Afr/Ap 25 Aug 010/012
Predicted Afr/Ap 26 Aug-28 Aug 012/015-013/018-009/012

VI. Geomagnetic Activity Probabilities 26 Aug-28 Aug
A. Middle Latitudes
Active 30/40/30
Minor Storm 10/20/10
Major-severe storm 01/05/01
B. High Latitudes
Active 15/10/15
Minor Storm 30/25/30
Major-severe storm 40/55/40